Electric discharging tube



l/VVE/V TOR BRUNO 170/104 r/=/ u lomuqum B.DONATH. ELECTRIC DISCHARGING TUBE.

APPLICATION FILED 'OCT, 1, 19M. 1,%16,623@

PatentedMay 16, 192' WITNESSES entree TATLES Parana @FFHQE.

ELECTRIC DISCHARGING TUBE.

masses.

application filed October 1, 1914.

Specification of Letters Patent.

Patented May M5, 1l@22. Serial No. seams.

(GRANTED ER THE PROVISIONS 015 THE ACT OF MARCH 3, 1921, l]. STAT. L, 1313.)

157,845). The object of the improvement is to increase the durability of'the said cathodes. I The smooth or rough cathode of the known discharging tubes have hitherto been provided with a thin covering' of any desiredmetallic combination, preferably calciumoxide. They were not very durable as a constant, althouthe oxide, takes cathodes. A thick layer of oxide would be liable to scale off, to heat irregularly and to produce a high ohmicresistance in the discharging circuit.

ccording-to the invention the discharging tubes. are provided with a cathode consisting of a perforated container of a refractory material of good electrical conductivity, for instance platinum, said container being filled with the metallic combiflat pocket the wa-l s referrin nations, preferabl calcium oxide. The container is Lpreferal given the form of a of which are made of thin perforated sheet. metal, Woven wire or the like. The outer sides ofthe container can of course also tallic' combinations.

My invention will be better understood by to the accompanying drawing in which ig. 1 represents a central diagrammatic' section, taken transversely to the cathode, through a discharge tube' having a cathode. accordin to-my inventionq'Fig. 2 is a perspective view, partly in section, on an enlarged scale, showing one end of the cathode of Fig. 1 when the container is made of sheet metal Fig. 3 is a view showing one end of a modified cathode as in Fig. 1; and Fig. 4 is a view, similar to Fig. 2, showin the cathode when the container is made of woven wire.-

at their ends so gh small, consumption of place in the working be'cov-ered with the me- In the drawings the bulb R is provided with anodes A and a cathode K; is, in the examples shown, held in clamps G which are themselves supported on conductors H.

In Fig. 2 the cathode container (7 consists oftwo strips of sheet metal which have been sultably shaped and united so as to provide an elongated receptacle the sides of which areperforated. The two strips are united as to fit into the clamps G. (Only one end of the cathode and one clamp are shown). The receptacle is filled with the desired metallic combination, preferably calcium oxide.

In Fig. 4 the cathode container consists of a strip of woven wirebent or rolled so as to constitute a receptacle of flattened cross section which is filled, as before, with the metallic combination folded and rcssed flat so as to close the receptacle and to fit the clamps G.

In Fig. 8 is shown one end of a short sec-- tion of the container as it appears when the metallic combination is placed upon its outside as well as contained within it.

The conductors H serve to conduct both heat and electrical current.

Having described my. invention, I claim l.' An electric discharge tube having a cathode adapted to become incandescent, comprising a container of refractory material and good electrical conductivity, said container having thin metallic perforated walls and a metallic combination therein there being also a coating of metallic combination on the outside of said container.

2. An electric discharge tube having a cathode adapted to become incandescent, comprising a container of refractory material and good electrical-conductivity, said container having thin metallic perforated walls, and enclosing calcium oxide, there bein also a coating of metallic combination ont eoutside. of said container.

In testimony whereof I have hereunto set my hand in the presence of two subscribing, witnesses.

BRUNO DONATH.

Witnesses WoLnEMAR HAUPT, HENRY Hasrna.

the latter 

